MECHANISM AND REGULATION OF ION TRANSPORT ACROSS THE RENAL TUBULE Our research project is directed toward clarification of unresolved problems of ion transport processes across the apical and basolateral membranes of proximal and distal nephron segments of mammalian nephrons. We shall apply tubule perfusion methods, exploration of ion conductances and of native ion channels by electrophysiological techniques, and measurements of cell ion concentrations by fluorometric and electron probe approaches. We will also collaborative in studies of cloning the CI- oxalate and CI-formate exchanger. We propose to take advantage of several hereditary mouse animal models in which ion carriers are either overexpressed or absent. Our focus will be on Na, K, CI and H transport mechanisms and their physiological regulation. We shall also investigate principle tubule cell signaling pathways that coordinate apical and basolateral transport processes.